EMF格式包含GDI信息，应用程序打印后让打印管理器(Spool)处理打印设备接口(device driver interface ),即打印驱动程序。
RAW格式为最终的打印文件，可直接打印或交给Spool,不再需要选择驱动程序，
WIN9X远程打印必须用RAW.
M$如是说：
Enhanced Metafile Spooling Architecture in Windows NT 4.0
PSS ID Number: Q155676
Article last modified on 01-18-1999
4.0
winnt
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The information in this article applies to:
- Microsoft Windows NT Workstation version 4.0
- Microsoft Windows NT Server version 4.0
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SUMMARY
=======
In Windows NT 4.0, Enhanced Metafile (EMF) spooling has replaced Windows NT 3.x
Journaling. This makes the Windows NT print model similar to the print model
used by Windows 95. EMF spool files are used to greatly reduce the amount of
time that elapses between a request to print (initiated by an application) and
the return of control to the application by the operating system.
MORE INFORMATION
================
Windows NT 4.0 implements EMF spooling by recording the graphic device interface
(GDI) function calls that produce the application's graphic object on the
specified printer. This record is an EMF-format file, called a print spool file.
Windows NT builds the spool file quickly, and then
returns control to the
application. In the background, the spool file is spooled to the server, and the
server converts the EMF data into a format suitable for the output device.
The bulk of the EMF print model is an array of variable-sized records that encode
the GDI function calls necessary to reproduce the picture when the EMF spool
file is played back. EMF spool files encode graphics information in such a way
as to maintain device independence.
NOTE: By default, Windows NT 4.0 enables EMF spooling for PCL and HPGL/2. EMF can
also be configured for PostScript printing;
however, the benefits are minimal
for client performance.
OTHER SPOOL FILE FORMATS
RAW: The raw data type indicates that the print job has already been fully
rendered by the GDI and device driver interface (DDI), and itdo
es not need any
more processing. Raw data streams can either be printed directly, or they can be
put into spool files. Most Windows NT printing clients send raw jobs. Raw spool
files are device-dependent. That is, the spooled data is destined and formatted
for a particular device anddo
es not need to be printable on any other device.
An example of a raw spool file is an encapsulated PostScript file, which is
formatted to be understood by the PostScript printer for which it is destined.
For more information, please see the following article in the Microsoft Knowledge
Base:
ARTICLE-ID: Q104902
(http://support.microsoft.com/support/kb/articles/Q104/9/02.ASP)
TITLE : Print Processors and Data Types
TEXT: When the data type of a print job is text, the print processor sends the
incoming job to the graphics engine. The graphics engine then
returns a print
job, which prints the original text using the print device's default paper
source, default font, orientation, margins, and duplexing. This achieves the
same result as saving the incoming job to a file, opening that file with
Notepad, and then
printing the job.
JOURNAL: The Windows NT JNL 1.000 data type (usually called "Journal") indicates
that the job is being sent from a Windows-based application (either 16- bit or
32-bit) running on the Windows NT print server. It also indicates that the
target printer was established in Print Manager using the Create Printer option.
In this case, the application uses GDI commands to describe the output. The
Windows NT GDI32 component and the printer driver partially render the print job
using DDI commands, and then
return control to the application. As a result, the
application finishes its print operation faster than normal. In the background,
GDI32 then
submits the DDI journal file to the spooler, with the data type set
to "NT JNL 1.000." The spooler then
calls GDI32 to finish rendering the job into
printer language commands.
The table below illustrates when EMF is used by Windows NT 4.0 Server.
Print Client EMF RAW
-----------------------------------------
Windows NT 4.0(1) 1 0
Windows NT 4.0(2) 0 1
Windows NT 3.x(1) 0 1
Windows NT 3.x(2) 0 1
Windows 95(3) 0 1
Windows for Workgroups 0 1
Non Microsoft Client 0 1
Notes:
(1) Indicates the server in the "Connected to" box. In Windows NT 4.0,
this occurs when you select Network Printer in the Add Printer
Wizard.
(2) Indicates that the driver is installed locally and is redirected to
the server share point.
(3) Windows 95 supports EMF, but always plays the EMF file locally and
spools to the server as RAW.
As indicated in the chart above, the only client that takes advantage of the EMF
spooling is a Windows NT 4.0 client using one of the following drivers:
* PCL
* PostScript
* HPGL/2
For each of those drivers, EMF spooling is enabled by default. If necessary,
users can turn off EMF spooling functionality on a per printer basis. Todo
this, perform the following steps:
1. In the Printers folder, click the printer whose properties you want to
change.
2. On the File menu, click Properties.
3. Click PrintProcessor.
4. Click the Always Spool RAW Datatype option.
Additional query words: prodnt sp1
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Keywords : ntprint NTSrvWkst kbprint
Version : 4.0
Platform : winnt
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Copyright Microsoft Corporation 1999.
